262 



AVES. 



Fi(f. 130. — Sternum of Bewick's Swan. 



ridge. They carry the neck more upright, and never elevate the tertial plumes. None of them has 



any protuberance on the base of the bill ; and they have all white 

 plumage with black feet, or, in the young, grey plumage with white 

 wings, and the feet white when newly hatched. They yield the swan's 

 down of commerce, which is much inferior both in quality and quan- 

 tity in the others ; and are restricted in their distribution to the 

 northern hemisphere. 



Of four species, two are respectively peculiar to each continent. 

 The Trumpeter Swan (C. buccinator) of America is the largest, and yields 

 most of the down of commerce, together with the next species. Its bill is 

 wholly black, and the trachea forms a double vertical convolution within the 

 sternal ridge, and is bifurcated into short inflated bronchi. 



Audubon's Swan (C. AudubonU and americana) is smaller, but fully equals 

 the European Hooper Swan in size, although it has been confounded with 

 C. Beicickii. Its bill has an orange-yellow spot on each side towards the base, 

 and the trachea forms a horizontal flexure within the inflated hind-margin of 

 the sternum, having similar bronchi to those of the last. 



Bewick's Swan (C. Beicickii) is considerably smaller, with exactly similar 

 tracheal apparatus, and a larger orange-yellow space at the base of the 

 bill, extending to the nostrils. Of seventeen specimens dissected by us, 

 one only presented the horizontal flexure of the trachea (represented 

 fiom the identical specimen in fig. 130), though several were evidently older 

 birds : but the inflated form of the bronchi constitutes an invariable distinc- 

 tion from the next species. Tail-feathers generally twenty, sometimes eighteen, and we have more than once met 

 with nineteen, where none had been lost. It is much less common in Britain, as a winter visitant, than the next. 

 The Hooper Swan (C. musicus, Anas cygmis, Lin.), or common Wild Swan of Europe, which visits Britain in 

 abundance in severe winters. The largest specimens are scarcely inferior in size to the Mute species, and have 

 the most extended brilliant-yellow space at the base of the bill of any, extending beyond the nostrils. The 

 trachea forms but a single vertical flexure, and the bronchi are much longer than in the others, and not inflated. 

 On dissecting a cygnet in its down, we found the cavity of the sternal ridge completely formed, but the trachea 

 did not enter. The tail-feathers are generally twenty, and sometimes twenty-one or twenty-two. All these birds 

 utter loud trumpeting cries, and the present species has also a low musical note, which is often repeated.] 



We can scarcely distinguish from the Swans certain species, which undoubtedly are less elegant, but 

 have the same beak. As 



The Knobbed Goose (Anas cyynoidcs, Lin.), which we rear in our poultry-yards, and which interbreeds readily 

 with the common domestic species. The base of its upper mandible is protuberant, as in the Mute Swan, and its 

 neck is whitish, with a dark streak passing down the back of it. [In every essential particular, this is a true 

 Goose, and has sixteen cervical vertebrae, like the rest of that genus. Its flesh is less highly esteemed than that 

 of the common bird ; than which, however, it is considerably more prolific, propagating at all seasons. As in the 

 other Geese, it seeks its food principally, or it may be said wholly, on land, and utters loud noisy cries.] 



The Spur-winged Goose (Anas Gambensis, Lin.).— Remarkable for its size, its elevated legs, the tubercle upon 

 its forehead, and the two stout spurs with which the bend of its wing is armed. Its plumage is empurpled black, 

 [very like that of a Musk Duck, to which this species is considerably allied, notwithstanding its long legs. It 

 forms the genus Plectroptents of Swainson. 



The author also includes among the Swans the Canada Goose (A. canadensis), which also possesses every 

 intrinsic character of the true Geese. It is a very large species, with a long black neck, and white mark across 

 the throat, as in the Black-necked Swan ; which is likewise readily domesticated, and breeds plentifully in Europe. 

 Another nearly allied (A. Hutchinsonii) has more recently been discovered in the same country — North America, 

 from which neither has been known to stray across the Atlantic in the wild state, though found very far to the 

 north. The first down of all the Geese is mottled, of the Swans plain.] 



The Geese (Anser, Brisson) — 

 Have the bill moderate or short, narrower in front than behind, and higher than broad at the base ; 

 the legs longer than in the Ducks, and placed nearer the middle of the body, to facilitate their gait 

 on land. They have no labyrinth at the bottom of the trachea, nor does the latter form any curve in 

 the know r n species. Several [all] feed on grass and grain. 



The Geese, properly so called, — 

 Have the bill as long as the head, with the ends of the lamellae extending to its edges, and appearing 

 like pointed teeth. 



[The last-mentioned character is most strongly developed in the Snow Goose (A. h/perborevs) of North America, 

 the adult male of which is white, with black primaries. This species rarely straggles into northern Europe. Four 



